1. Technical Field
The present invention relates to an organic light-emitting device and an image display system employing the same, and in particular, relates to an organic light-emitting device with high light extraction efficiency and an image display system employing the same.
2. Description of the Related Art
Recently, with the development and wide application of electronic products, such as mobile phones, PDAs, and notebook computers, there has been increasing demand for flat display elements which consume less electric power and occupy less space. Organic light-emitting devices are self-emitting and highly luminous, with wide viewing angles, fast response speeds, and simple fabrication methods, making them the best selection of the next generation flat panel display.
An organic light-emitting device is an LED that uses an organic layer as the active layer. In recent years, organic light-emitting devices have been gradually applied in flat panel displays. One trend in organic light-emitting device technology is to achieve high luminescent efficiency and long operating lifetimes.
As shown in FIG. 1, a conventional organic light-emitting device 10 includes a bottom substrate 12, organic light-emitting pixel structure 14 (including sub-pixels 14a-14d), a filling layer 16, a spacers 18, a black matrix 20, a color filter layer 22 (including red, blue, and green color filter layers), and a top substrate 24. In the conventional organic light-emitting device 10, since the organic light-emitting pixel structure 14 has a metal electrode (with high reflectivity) serving as an anode, a polarizing film 26 is further formed on the top substrate 24 in order to reduce the intensity of reflected light L′ produced from the ambient incident light L, enhance the contrast of the image display system, and increase the usefulness for outdoor use.
At the present time, due to the poor transmittance (40˜45%) of the polarizing film, the polarizing film 26 reduces the brightness of light produced from the organic light-emitting pixel structure 14 when shielding the ambient light, thereby reducing the light extraction efficiency and electroluminescent efficiency of the image display system 10 simultaneously. Hence, the driving voltage of the image display system 10 is increased for maintaining the brightness, resulting in reduced operating lifetime.
Accordingly, a novel organic light-emitting device having high light extraction efficiency which overcomes the above difficulties and inconveniences is desired.